From the Italian patent application No. 3376 A/87 corresponding to my copending U.S. application No. 07/154,782 filed Feb. 10, 1988, an automatic machine is known for the continuous production of dual-use filter sachets for infusion products. Such dual-use sachets comprise two containment bags or pouches containing fractional doses of the infusion products. The machine comprises along the production line a succession of means for making the dual-use sachets including at the upstream side of the manufacturing path a means designed to progressively fold and longitudinally seal a strip of thermally weldable filter paper fed with the fractional doses having a flattened tubular form and oriented horizontally. This means is followed by a means for thermally welding the tube transversely so as to enclose individual fractional doses between two of said successive thermal weld.
A means with rotating wheels having pickup elements then applies to the flattened tube equidistantly spaced labels, a continuous longitudinal thread transversely contacting said labels, as well as thermally weldable stickers or tabs across alternate transverse thermal welds partly to the back of said labels.
The tube then encounters means for cutting the tube into pieces comprising at least two pouches each and for setting up said bags adjacently and for sealing together their extremities.
More particularly, such a dual-use sachets of filter paper with multiple successive or serieal bags or pouches each containing a corresponding fractional dose or unit quantity of the infusion products, has a structure with two arrangements of use, namely one in its flattened form packaged for sale in lots with said bags or pouches arranged superimposed on each other or arranged back to back by folding one bag or pouch over the adjacent one, and in an unfolded or extended arrangement of said pouches following action by pressing and pulling by the user of the corresponding label covering the handling thread of the said filter sachet. The said thread has a length which is substantially equal to the length of the sachet in its position with unfolded bags or pouches, and is fastened to the opposite extremity of the sachet by means of a sticker or tab made of thermally weldable material jointly with the label made of nonthermally weldable paper in proximity to one of these opposite extremities and is arranged to pass longitudinally around the outside of the sachet when the bags or pouches are stacked in lots for sale with the pouches folded back to back.